Diwali, the Vedic Festival of Lights occurs at the New Moon in the lunar month of Kartika. It symbolizes the new year and the triumph of light over darkness, and this year falls on Thursday 23rd October. For those of us living in the Frozen North (aka, London) it is a very welcome celebration, just as the clocks go back and we're plunged into darkness.
The above chant is Sri Suktam, a famous Sanskrit hymn in praise of Mahalakshmi, from the Rig Veda. In 16 verses (slokas), Lakshmi is addressed as the bestower of fame and abundance in the form of gold and food, and entreated to banish her sister Alakṣmī, who is associated with need and poverty. The English translation is given.
This year the Diwali New Moon happens to be a partial Solar Eclipse, which occurs at 09:45pm GMT, in the constellation of Chitta. Eclipses are especially auspicious times to perform chanting and puja.
I personally will be attending Diwali celebrations at the the Shri Swaminarayan Mandir in north London: http://londonmandir.baps.org/forthcoming-events/diwali-2014/
Enjoy!